First-principles study of the effect of doping on the optoelectronic properties of defective monolayers of MoSe2

Dan Su; Guili Liu; Mengting Ma; Ran Wei; Yansong Mu; Zhonghua Yang; Guoying Zhang

doi:10.1007/s00894-023-05826-8

First-principles study of the effect of doping on the optoelectronic properties of defective monolayers of MoSe₂

J Mol Model. 2024 Jan 9;30(2):29. doi: 10.1007/s00894-023-05826-8.

Authors

Dan Su¹, Guili Liu², Mengting Ma¹, Ran Wei¹, Yansong Mu¹, Zhonghua Yang¹, Guoying Zhang³

Affiliations

¹ College of Architecture and Civil Engineering, Shenyang University of Technology, Shenliao Westroad Economic and Technological Development District, No.111, Shenyang, Liaoning, People's Republic of China.
² College of Architecture and Civil Engineering, Shenyang University of Technology, Shenliao Westroad Economic and Technological Development District, No.111, Shenyang, Liaoning, People's Republic of China. garylll@sina.com.
³ School of Physics, Shenyang Normal University, Shenyang, People's Republic of China.

PMID: 38194004
DOI: 10.1007/s00894-023-05826-8

Abstract

Context: In this paper, the structural stability, electronic structure, and optical properties of monolayer MoSe₂ doped with C, O, Si, S, and Te atoms, respectively, under defective conditions are investigated based on first principles. It is found that the system is more structurally stable when defecting a single Se atom as compared to defecting a single Mo or two Se atoms. The electronic structure analysis of the system reveals that intrinsic MoSe₂ is a direct bandgap semiconductor. The bandgap value of the system decreases with a single Se atom defect and introduces two new impurity energy levels in the conduction band. The defective systems doped with C and Si atoms all exhibit P-type doping. The total density of states of intrinsic MoSe₂ is mainly contributed by the Mo-d and Se-p orbitals, and new density of state peaks appears near the conduction band after the defects of Se atoms. The total density of states of the defective system doped by each atom is mainly contributed by Mo-d, Se-p, and the result of the p orbital contribution of each dopant atom. By analyzing the dielectric function of each system, it is found that the intrinsic MoSe₂ has the lowest static permittivity and the C-doped defect system has the highest static permittivity, which reaches 21.42. The C- and Si-doped defect systems are the first to start absorbing the light, and the intrinsic MoSe₂ absorbs the light later, with its absorption edge starting at 1.25 eV. In the visible range, the reflection peaks of the systems move toward the high-energy region and the blue-shift phenomenon occurs. It is hoped that applying modification means to modulate the physical properties of the two-dimensional materials will provide some theoretical basis for broadening the application of monolayer MoSe₂ in the field of optoelectronic devices.

Methods: This study utilizes the first principle computational software package MS8.0 (Materials studio8.0) under density functional theory (DFT). The exchange-correlation potential (GGA-PBE) is described by the Perdew-Burke-Ernzerhof correlation function in CASTEP, and the potential function adopts the ultrasoft pseudopotential in the inverse space formulation. The plane wave truncation energy E_cut is set to 400 eV, the K-point is taken as 5 × 5 × 1, and the force convergence criterion is 0.05 eV/Å. The convergence accuracy of the total energy of the system is less than 1.0 × 10^-5 eV/atom, the tolerance shift is less than 0.002 Å, and the stress deviation is less than 0.1 GPa. The vacuum layer is taken as 15 Å, which is intended to minimize the interlayer force. The vacuum layer was set to 15 Å to avoid the effect of layer-to-layer interaction forces in the crystal cell.

Keywords: Defects; Doping; Intrinsic MoSe2; Optoelectronic properties.

Abstract

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